Emulsion stabilization via silicilic acid complexation

Abstract

Disclosed are methods of preparing stable O/W emulsions by silicic acid complexation of micron-sized oil droplets, and stable emulsions prepared by silicic acid complexation. Compositions and products comprising the emulsions are also disclosed. Emulsions may be stable over an extended period of time at room temperature.

What is claimed is: 
     
       1. A method for preparing an emulsion, said method comprising:
 preparing an O/W dispersion comprising at least one cationic surface active adsorbed to the oil-water interface such that oil droplets have a cationic surface; 
 preparing a solution comprising at least one dissolved silicate salt; 
 adjusting the pH of the solution comprising the at least one dissolved silicate salt to a range of from about 6.0 to about 9.0 to create anionic complexes; 
 mixing the O/W dispersion and the solution comprising at least one dissolved silicate salt such that the anionic complexes are attracted to the cationic surface of the oil droplets, resulting in encapsulated oil droplets. 
 
     
     
       2. The method according to  claim 1 , wherein the size of the oil droplets ranges from about 0.1 μm to about 500 μm. 
     
     
       3. The method according to  claim 1 , wherein the volume of the oil phase in the O/W dispersion ranges from about 5% to about 50%. 
     
     
       4. The method according to  claim 1 , wherein the oil phase comprise at least one oil chosen from triglycerides, esters, ethers, silicones, and volatile oils, or at least one oily compound chosen from sunscreen filters, vitamins, and lipophilic molecules dissolved in oil. 
     
     
       5. The method according to  claim 1 , wherein the concentration of the at least one cationic surface active agent ranges from about 1 to about 25 times Critical Micellar Concentration. 
     
     
       6. The method according to  claim 1 , wherein the at least one cationic surface active agent is chosen from optionally polyoxyalkylenated primary, secondary and tertiary fatty amines, quaternary ammonium salts, and mixtures thereof. 
     
     
       7. The method according to  claim 1 , wherein the at least one cationic surface active agent is chosen from at least one amphoteric surface active agent that has been pH-adjusted to be cationic. 
     
     
       8. The method according to  claim 7 , wherein the at least one cationic surface active agent chosen from at least one amphoteric surface active agent that has been pH-adjusted to be cationic is chosen from derivatives of betaine, derivatives of alkylamphoacetate, derivatives of hydroxylsultaines, and mixtures thereof. 
     
     
       9. The method according to  claim 1 , wherein the solution comprising at least one silicate salt has a concentration ranging from about 0.05 M to about 0.3 M. 
     
     
       10. The method according to  claim 1 , wherein the at least one silicate salt is chosen from disodium silicate, calcium silicate, magnesium silicate, sodium silicate, aluminum silicate, potassium silicate, zirconium silicate, tetramethylammonium silicate, sodium alumino silicate, potassium methyl siliconate, sodium methyl siliconate, and mixtures thereof. 
     
     
       11. The method according to  claim 1 , wherein mixing the O/W dispersion and the solution comprising the at least one silicate salt comprises mixing the O/W dispersion and the solution comprising at a ratio of silicate solution: O/W dispersion ranging from about 20:80 to about 80:20. 
     
     
       12. A method for preparing an emulsion, said method comprising the steps of:
 a. preparing an aqueous solution having at least one cationic surface active agent; 
 b. preparing an oil phase; 
 c. mixing said aqueous solution having at least one cationic surface active agent and said oil phase to obtain an O/W dispersion comprising oil droplets having a cationic surface; 
 d. preparing a solution comprising at least one dissolved silicate salt; 
 e. adjusting the pH of the solution comprising the at least one dissolved silicate salt to a range of from about 6.0 to about 9.0 to create anionic complexes; and 
 f. mixing the O/W dispersion and the solution comprising the at least one dissolved silicate salt such that the anionic complexes are attracted to the cationic surface of the oil droplets, resulting in encapsulated oil droplets. 
 
     
     
       13. The method according to  claim 12 , wherein the size of the oil droplets ranges from about 0.1 μm to about 500 μm. 
     
     
       14. The method according to  claim 12 , wherein the volume of the oil phase in the O/W dispersion ranges from about 5% to about 50%. 
     
     
       15. The method according to  claim 12 , wherein the oil phase comprise at least one oil chosen from triglycerides, esters, ethers, silicones, and volatile oils, or at least one oily compound chosen from sunscreen filters, vitamins, and lipophilic molecules dissolved in oil. 
     
     
       16. The method according to  claim 12 , wherein the concentration of the at least one cationic surface active agent ranges from about 1 to about 25 times Critical Micellar Concentration. 
     
     
       17. The method according to  claim 12 , wherein the at least one cationic surface active agent is chosen from optionally polyoxyalkylenated primary, secondary and tertiary fatty amines, quaternary ammonium salts, and mixtures thereof. 
     
     
       18. The method according to  claim 12 , wherein the at least one cationic surface active agent is chosen from at least one amphoteric surface active agent that has been pH-adjusted to be cationic. 
     
     
       19. The method according to  claim 18 , wherein the at least one cationic surface active agent chosen from at least one amphoteric surface active agent that has been pH-adjusted to be cationic is chosen from derivatives of betaine, derivatives of alkylamphoacetate, derivatives of hydroxylsultaines, and mixtures thereof. 
     
     
       20. The method according to  claim 12 , wherein the solution comprising at least one silicate salt has a concentration ranging from about 0.05 M to about 0.3 M. 
     
     
       21. The method according to  claim 12 , wherein the at least one silicate salt is chosen from disodium silicate, calcium silicate, magnesium silicate, sodium silicate, aluminum silicate, potassium silicate, zirconium silicate, tetramethylammonium silicate, sodium alumino silicate, potassium methyl siliconate, sodium methyl siliconate, and mixtures thereof. 
     
     
       22. The method according to  claim 12 , wherein mixing the O/W dispersion and the solution comprising the at least one silicate salt comprises mixing the O/W dispersion and the solution comprising at a ratio of silicate solution: O/W dispersion ranging from about 20:80 to about 80:20.